The present invention relates to diaphragm pumps.
Micro pumps taking up little installation space have been known from conventional technology. For example, from DE 197 19 862 A1, a micro diaphragm pump comprising passive check valves has been known which comprises a pump diaphragm that is movable into first and second positions by means of driving means. A pump body is connected to the pump diaphragm to define a pump chamber between them. An inlet opening and an outlet opening are each provided with passive check valves. In addition to a piezoelectric drive for the pump diaphragm, an electrostatic drive has also been described. The pump diaphragm and check valves are structured in respective silicon substrates. In addition, starting materials mentioned for the pump diaphragm are, in addition to silicon, glass or plastic.
Typical dimensions of known micro diaphragm pumps in the form of silicon pumps with piezo drive are 7×7×1 mm3. In addition, plastic pumps with piezo drive have been known.
A micro peristaltic pump consisting of a base element and a diaphragm element is described in DE 102 38 600 A1. The base element has three fluidically interconnected chambers formed therein whose volumes are independently variable by the diaphragm element by means of actuating means. Two chambers represent valve chambers, whereas one chamber represents a pump chamber. The base element may be injection-molded from plastic or be machined, by means of precision engineering, from a suitable material, for example metal. The diaphragm element may be formed from silicon, a metal foil or an elastomer diaphragm. In addition to piezo actuators, electrostatic actuators or pneumatic drives for the diaphragm areas have been mentioned.
Micro pumps that have been described in conventional technology and offered on the market have a maximum delivery rate of 10 to 20 ml/min for water, and a maximum of 100 ml/min for air.
For micro peristaltic pumps, the fluid to be pumped, i.e. the liquid or gas, may be moved through a long and narrow channel during each pump cycle, the corresponding forward resistances being high. Therefore, micro peristaltic pumps deliver smaller volumes, while taking up the same amount of installation space, than micro diaphragm pumps having passive check valves.